Field of the Invention
The present application relates to devices and methods for treating cancer using brachytherapy. In particular, the present application relates to devices and methods for treating cervical and/or uterine cancers in brachytherapy with an intracavitary brachytherapy applicator.
Description of the Related Art
“Brachy” is derived from the Greek word “brachio” meaning short range, and in reference to brachytherapy is defined as “Short Range Treatment with a Radioisotope.” Five years after 226Ra was discovered by Marie and Pierre Curie in Paris, Alexander Graham Bell suggested the implantation of radioactive sources directly into the tumors. That same year in 1903, two cases of facial basal cell carcinoma were treated, using 226Ra surface molds in St. Petersburg.
Brachytherapy typically offers low morbidity by delivering a high dose of ionizing radiation to the target volume, sparing surrounding healthy tissue with rapid dose fall off outside the implanted volume. Selective placement of the radioactive sources allow the dose distribution to be manipulated to match the target shape. Brachytherapy can be used in treating most areas of the body and can be used alone or in conjunction with External Beam Radiotherapy, Chemotherapy, and Surgery for management of cancer. HDR and LDR brachytherapy are well-established techniques with a long history of use in treatment of cervical and uterine cancers. The scientific principle behind this technology is that a highly radioactive source inside an afterloader passes through a transfer guide tube into an applicator implanted in the patient. The radioactive source is programmed to remain in its precise location for a given period to deliver radiation dose according to the prescription. This can be effective in treating cancers of the cervix and uterus.
One known applicator for use in brachytherapy is the Fletcher-Suit-Delclos (FSD) afterloading intracavitary brachytherapy applicator for treatment of cervical and uterine cancers. Intracavitary brachytherapy procedure using FSD applicator for treatment of cervical and uterine cancers is tedious and time consuming. The procedure requires the patient to be consciously sedated or anesthetized as the procedure can be painful and lengthy with the complex design of the current available applicators requiring one to two nurses in assisting the radiation oncologist in implanting the applicator. The non-ideal geometry of the applicator placement, and the inadequate and occasionally painful placement of the vaginal packing retractor used to retract the bladder and the rectum from the plane of the implant, make the radiation dosimetry non-ideal, with high doses reaching the bladder or the rectum causing unwanted morbidities in some cases. Accordingly, in order to keep the radiation dose within the respective tolerance doses of the organs at risk, in some cases a user lowers the dose to the tumor; thus potentially causing the cancer to reoccur. Some optimization algorithms are currently used in the HDR treatment planning systems, however these cannot and do not adequately substitute or replace a geometrically optimum implant.
In recent years many intracavitary applicators based on the FSD applicator concept have been designed, and used in the clinic, e.g., the Week, Williamson, Henschke and Mick applicators. The typical prescription requires 3 or 4 implants, one week apart, on the same patient. The traditional FSD applicator normally consists of 8-pieces assembled as the patient rests supine in the stirrup position. The current clinical procedure using FSD applicator is typically lengthy, painful, and often requires anesthetics, or conscious sedation. The problems outlined herein have made patients request alternative treatments such as surgery or use of Intensity Modulated Radiotherapy (IMRT). However, the intracavitary brachytherapy for treating cervical and uterine cancers should not be replaced with IMRT since intracavitary brachytherapy provides more conformal therapy, less integral dose, and superior sparing of the organs at risk.